[PATCH v1] x86: Remove wcsnlen-sse4_1 from wcslen ifunc-impl-list [BZ #28064]

[Noah Goldstein]

The following commit

commit 6f573a27b6c8b4236445810a44660612323f5a73
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Jun 23 01:19:34 2021 -0400

    x86-64: Add wcslen optimize for sse4.1

Added wcsnlen-sse4.1 to the wcslen ifunc implementation list and did
not add wcslen-sse4.1 to wcslen ifunc implementation list. This commit
fixes that by removing wcsnlen-sse4.1 from the wcslen ifunc
implementation list and adding wcslen-sse4.1 to the ifunc
implementation list.

Testing:
test-wcslen.c is passing as well as all other tests in wcsmbs and
string.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
---
I was unable to actually reproduce the bug on my machine, even after
reordering ifunc-wcslen.h to prefer the sse4.1
implementation. Although this most definetly is a bug.


I ran the following command. Is there an issue with the command? Or
does rdx happen to always have a len >= actual length of the string?

$> rm -rf build; mkdir -p build/glibc; (cd build/glibc/; unset LD_LIBRARY_PATH; /absolute/path/to/src/glibc/configure --prefix=/usr; make --silent; make xcheck; make -r -C /absolute/path/to/src/glibc/string/ objdir=`pwd` check; make -r -C /absolute/path/to/src/glibc/wcsmbs/ objdir=`pwd` check);


        
 sysdeps/x86_64/multiarch/ifunc-impl-list.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index dbd1ebf298..39ab10613b 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -684,9 +684,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (AVX512BW)
 			       && CPU_FEATURE_USABLE (BMI2)),
 			      __wcslen_evex)
-	      IFUNC_IMPL_ADD (array, i, wcsnlen,
+	      IFUNC_IMPL_ADD (array, i, wcslen,
 			      CPU_FEATURE_USABLE (SSE4_1),
-			      __wcsnlen_sse4_1)
+			      __wcslen_sse4_1)
 	      IFUNC_IMPL_ADD (array, i, wcslen, 1, __wcslen_sse2))
 
   /* Support sysdeps/x86_64/multiarch/wcsnlen.c.  */
-- 
2.25.1